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Quality counts when trucks go in for preventative maintenance

By on March 7, 2014

Whether you are a one-truck operation or manage a fleet with thousands of vehicles, the single most important control you have for sustaining and improving profitability is a relatively simple one. Prevent costly breakdowns and unscheduled maintenance events by sticking to a quality Preventative Maintenance Inspection (PMI) program.

This is about more than merely changing the oil and filters according to the user’s manual. Some drivers and fleet managers focus on that part of the process and think that performing preventative maintenance is a trivial task that requires little technical expertise.

But a quality PMI involves so much more. The PMI technician must be able to quickly evaluate almost every system on a vehicle to determine its current state and project its future life. They look at a whole range of systems, including brakes, steering, electrical, cooling and so on.

It takes a wealth of knowledge and experience to detect those sometimes elusive indicators of a potential mechanical defect. Expertise is necessary to spot a 90-degree air fitting in a location that requires a straight air fitting, for example. That installation error is the equivalent of having an extra seven feet of airline, and can affect brake timing. A PMI technician must be able to see this type of defect and understand its potential negative impact.

Triple L and a W

I like to say that a quality PMI is all about the Triple L and a W — loose components, leaks, lube and wear.

Loose components must be detected in order to avoid expensive repairs later. Shiny metal, loose washers, shifting components and excessive wear can indicate that a bolt or cap screw is loose and must be checked before the vehicle is placed back in service. This requires a trained eye and attention to detail, which means it can be done quickly, but can’t be rushed. It’s worth the effort. Identifying a loose mounting bolt and correcting it can save an owner-operator or fleet several thousand dollars.

Determining the severity of leaking components can be tricky. It’s common for some technicians to see a “weep” and call it a leak. Many seals have a small level of seepage that leaves a bit of oil, coolant or fuel in the vicinity of the seal. No truck operator wants to pay for unnecessary repairs, and an experienced, trained tech can decipher which level of leak is a concern and which one is normal.

Properly lubricating a vehicle is a critical component of PMI. Adding fresh grease is only part of the procedure. Flushing the old grease and contamination is equally important. Technicians who possess the knowledge and expertise can evaluate the condition of the old grease and contamination to determine if the component may have been permanently damaged. For example, a technician may see that the old grease purged from a U-joint has a dark black appearance — which indicates that the U-joint has failed. If rusty water is purged, it indicates that the needle bearings are rusty. In both cases the U-joint must be replaced.

Using your senses

Some components get more use than others, so knowing what and how to measure wear during a scheduled maintenance inspection is a key factor for controlling maintenance costs. Obviously, brake shoes must be measured periodically to determine usable life. But determining the condition of additional brake components like s-cam bushings, brake drums and slack adjusters is trickier.

Knowledgeable techs understand where to look and what to look for, but also bring in other senses, like touch, to determine a component’s condition. They know when to use instruments such as feeler gauges and dial indicators, and stay on top of the ever-evolving variety of new tools and how to properly use them to gain productivity. Knowing the life expectancy of normal wear items and using that information to schedule replacements is another big factor in controlling costs.

Everyone knows the importance of preventative maintenance. But the quality of that PMI is key to the balance sheet. It can be the difference between being in the red or being in the black.  o

Homer Hogg, Technical Training Manager for TA and Petro, has worked as a truck technician for more than 30 years. He is ASE Master-certified, a Daimler Certified Trainer and a member of the Nashville Auto Diesel College Hall of Fame.

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